GroupMe sends more than 100 million texts per month and has a few million users. It has also been partnering with major brands like Oxygen.

The two companies have been in talks for a few months, says Skype CEO Tony Bates. "The GroupMe team has created an incredibly sticky group messaging experience that works across mobile devices and platforms, making this a perfect addition to to the voice, video and text products in the Skype family," says Bates.

Bates hints that Skype will use GroupMe's technology in tandom with mobile video provider Qik, which Skype acquired earlier this year.

It's a smart move for GroupMe, which was facing competition from Facebook messages, Apple's iMessage, and Google+.